"Manual TCU"

[92AWDTalonTSI]

I want to take apart an incompatible TCU that I have, solder in a breadboard and make a custom circuit that emulates a TCU. Now the only thing I need to figure out is the pulse attributes for line pressure. I know some people change the line pressure by adding a resistor. Thus making the signal weak and restricting less flow resulting in a higher pressure.

I want to emulate the pulse width for every gear change. Well, at least a close average. So that in first gear it emulates an accurate pressure for a 1-2 shift. So on and so forth. But while WOT do no modulation resulting in a hard shift. I cannot imagine at this moment what the modulation rate would be. But I don't figure something outrageously fast. Maybe in a lower gear? At any rate. I have a not so usable TCU (MD750093) that will shift my car. Albeit at the wrong points. I wonder if I could measure the modulation to get an understanding of line pressure.

 

[jrohner]

Pressure is adjusted with Pulsewidth Modulation. Just get or build a PWM controller, and have it so it's used at partial throttle and not at all above 50% throttle (or wherever you want it).

 

[92AWDTalonTSI]

Well, at what width is the modulation? I want something I can tie into the TPS output assuming that is how the TCU does it. I can then dial in the width via various pots. Emulating a TCU.

Something like this should work with some modification.

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[HighPSI TSi Guy]

First you need to understand how the PCS works, how the pulsewidth modulation works, and how the transmission uses the line pressure to fully understand what you need to build. You also need to understand why a resister on a PWM signal is not a proper modification.